function randomColor() {
    var colorArray = ["#FF9966", "#FF6666", "#6FB934", "#3194EC"];
    var tempColor = 0;
    var randomNum = 0;
    $(".main-article li").each(function(i, item) {
        randomNum = Math.floor(Math.random() * colorArray.length);
        while (tempColor == randomNum) {
            randomNum = Math.floor(Math.random() * colorArray.length);
        }
        $(item).css("background", colorArray[randomNum]);
        tempColor = randomNum;
    });
};
